Help with lab interpretation !

My understanding was chances of Lupus (SLE) is low if Sm antibodies and dsDNA is negative? My reference book tells me otherwise. The antibodies overlap in each disease. I am having difficulty how to distinguish between Lupus with secondary Sjogren's (Vs.) primary Sjogren's?

Based on above lab, my diagnosis is Scleroderma and Sjogren's Syndrome? I might be wrong but help me out here.

Q 1. But could it be primary SLE with secondary Sjogren's?
Q 2. Could it be just SLE? (which I doubt but help me please)
Q.3. Could it be just Sjogren's?

Last edit by reeya on Jul 19, '13

Enjoy this?

Join thousands and get our weekly Nursing Insights newsletter with the hottest, discussions, articles, and toons.

7

7

6

6

The primary differential from that series is diffuse scleroderma with a possible sjogren overlap. What is the patient's age? You should refer management to a rheumatologist who can manage the patient and likely also collaborate with other specialists as well (nephrology, pulmonology, cardio, gi). Im assuming the patient is female, so once that diagnosis is confirmed you should also refer to genetics or immunology to have her HLA genes sequenced as their can be other overlap susceptibilities beyond sjogrens. This can be done at any local academic hospital.

Thank you for your response. If you don't mind telling me how were you able to distinguish from the series that it is diffuse scleroderma and not limited scleroderma? Patient is in her early 40s (F). I have already referred her to a rheumatologist. It is good to know about the HLA gene sequencing. I will discuss about it on her next visit. So safe to say from the above series she does not have SLE right?

I wouldn't immediately suspect SLE due to the negative dsDNA and negative RNP. You can go ahead and run anti-smith antibodies to verify; however, at her age I would also imagine that she has either had clinical manifestations of lupus by now or not. I leaned towards diffuse as most labs automatically run an ACA (which would be indicative of limited if positive) when seeing a positive Scl 70. Im not sure what was or not done in this case so you can go ahead and order the following: ACA (indicates limited if positive), anti-RNA pol I/III (indicates diffuse if positive...Other tests which would be especially helpful to send over to the rheumatologist if she has not already been seen by them are: anti-U3RNP, anti-PM-Scl, and anti-U1RNP. One way or another they will most likely put her on an immunosuppresive regimen. If you are going to be the patients primary care provider you will have to be cognizant as she will have compromised immune functioning. Also, look out for management of drug interactions and regularly monitoring blood pressure, renal function, lung function, and heart function.

Her Sm antibodies were negative as well. She might have other underlying condition. ACA and anti RNA pol I/III was not run last time but good to know to differentiate the type of scleroderma. I am her PCP and very aware of compromised immune system. She never had any other medical issues ever except occasional cold/cough/fever/allergies. She was not taking any meds regularly. Very healthy person. When she came in this time, she had multiple vague symptoms. It is very scary people can be very healthy and all of a sudden can be so sick.

Wow, what a great thread....question---say you have a pt with elevated sed rate and positive ANA titer...vague symptoms, joint pains, fatigue, general malaise.....what labs would you order next?? I had pt today w/this scenario, and the specific labs were overwhelming...I wasn't sure if you go ahead and do all of the labs to rule out the majority of autoimmune diseases, or is there a method to the madness?

I would NOT order a full autoimmune panel on that patient. These tests are not cheap and are each actually quite complex for the labs to do. I think it would be clinically inefficient and frankly unfair to bill the patient for all of them especially if nothing conclusive results from them (which is the most likely scenario). It is crucial to understand the indications, sensitivity, specificity, cost and clinical utility of these tests. Several studies have suggested that overuse of common serum rheumatologic tests leads to unnecessary referrals and further laboratory work-ups. Failure to use these tests in a knowledgeable and thoughtful manner can result in diagnostic confusion and increased costs all around. As someone who has been a practicing NP for longer than most new grads have been alive, I would personally refer a patient like that to a physician.